Smoke exhauster having improved fan device

ABSTRACT

A smoke exhauster includes a motor attached to a housing, and a fan device attached to the motor and to be driven by the motor. The fan device including an upper plate, a lower plate having a bore, and a number of fan blades secured between the upper and the lower plates to form a chamber between the upper and the lower plates and to allow air to flow into the chamber of the fan device via the bore of the lower plate. Each of the fan blades includes a lower cut-off portion to allow the air to flow deeper into the chamber of the fan device before contacting with or scooped by the fan blades.

The present invention relates to the U.S. patent application Ser. No.10/000,307, filed 4 Dec. 2001, pending.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a smoke exhauster, and moreparticularly to a smoke exhauster having an improved fan device forincreasing the air drawing effect thereof.

2. Description of the Prior Art

The applicants have developed various kinds of typical smoke exhausterswhich comprise one or more centrifugal fan devices each having a fancasing and a number of radially extended fan blades directly punched orforged or extended from the fan casing.

For example, U.S. Pat. No. 5,979,436 to Chiang et al. discloses one ofthe typical smoke exhausters. Due to the directly punching or forming ofthe fan blades from the fan casing, the fan blades may only be formedwith a single curvature and may include a limited or a small area foractuating the air.

The present invention has arisen to mitigate and/or obviate theafore-described disadvantages of the conventional smoke exhausters.

SUMMARY OF THE INVENTION

The primary objective of the present invention is to provide a smokeexhauster including an improved fan device for increasing the airdrawing effect to the fan device.

In accordance with one aspect of the invention, there is provided asmoke exhauster comprising a housing, a motor attached to the housing,and a fan device attached to the motor and to be driven by the motor.The fan device includes an upper plate, a lower plate which has a boreformed therein, and a plurality of fan blades secured between the upperplate and the lower plate, to define a chamber between the upper plateand the lower plate of the fan device. The chamber of the fan device iscommunicating with the bore of the lower plate to allow air to flow intothe chamber of the fan device, and each of the fan blades includes alower cut-off portion formed therein to allow the air to flow deeperinto the chamber of the fan device before contacting with the fanblades.

The upper plate and the lower plate each includes a plurality of slitsformed therein, each of the fan blades includes an upper portion and alower portion each having at least one ear extended therefrom andengaged through the slits of the upper and the lower plates, forsecuring the fan blades between the upper and the lower plates.

Each of the fan blades includes an inclined edge defined by the lowercut-off portion thereof, and includes an inner segment, an intermediatesegment, and an outer segment, the outer segment of the fan bladeincludes a width no greater than that of the lower plate of the fandevice.

The inner segment of the fan blade includes a height smaller than thatof the intermediate segment and the outer segment of the fan blade. Theouter segment of the fan blade includes a width smaller than that of theinner segment and the intermediate segment of the fan blade. Theintermediate segment of the fan blade includes a curvature greater thanthat of the inner segment of the fan blade. The intermediate segment ofthe fan blade includes a curvature less than that of the outer segmentof the fan blade.

Further objectives and advantages of the present invention will becomeapparent from a careful reading of the detailed description providedhereinbelow, with appropriate reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial exploded view of a smoke exhauster in accordancewith the present invention;

FIG. 2 is a perspective view of the fan device of the smoke exhauster;

FIG. 3 is a partial exploded view of the fan device of the smokeexhauster;

FIG. 4 is a top plan view of the fan device, in which a portion of theupper plate of the fan device has been cut off for showing the innerstructure of the fan device;

FIG. 5 is a cross sectional view taken along lines 5—5 of FIG. 4;

FIG. 6 is a perspective view showing one of the fan blades of the fandevice;

FIG. 7 is a top plan view of the fan blade of the fan device; and

FIG. 8 is a bottom plan view illustrating the operation of the fandevice of the smoke exhauster.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings, and initially to FIG. 1, a smoke exhauster inaccordance with the present invention comprises a housing 10, a motor 11secured to the ceiling or the top panel 13 of the housing 10, and a fandevice 30 attached or secured to the spindle 12 of the motor 11 forbeing actuated or driven by the motor 11. The top panel 13 of thehousing 10 includes an orifice 14 formed therein for air circulationpurposes.

A casing 16 is engaged onto the fan device 30 and secured to the toppanel 13 of the housing 10, for covering or shielding the peripheralportion of the fan device 30, and includes an opening 17 formed thereinand aligned with the fan device 30, for allowing air to be drawn intothe casing 16 by the fan device 30. The casing 16 includes a conduit 18formed or provided therein and directed toward the orifice 14 of thehousing 10 for directing the air out through the orifice 14 of thehousing 10.

A board 15 is attached or secured to the bottom of the housing 10 forcovering or shielding the housing 10, and includes an aperture 19 formedtherein and aligned with the opening 17 of the casing 16 and the fandevice 30, for allowing the air to be drawn through the aperture 19 ofthe board 15 and to be drawn into the casing 16 by the fan device 30.

Referring next to FIGS. 2-6, the fan device 30 includes an upper plate31 having a recess or depression 32 formed in the upper portion thereoffor receiving the lower portion of the motor 11, and having a hub 33attached thereto for receiving or for securing to the spindle 12 of themotor 11. The upper plate 31 includes an outer peripheral portion havinga number of slits 34 formed therein, particularly having a number pairsof slits 34 formed therein (FIG. 3).

A lower plate 36 is disposed below the upper plate 31 and to be securedto the upper plate 31 with a number of fan blades 40, and for forming achamber 37 between the upper and the lower plates 31, 36. The lowerplate 36 includes a bore 38 formed therein and communicating with thechamber 37 of the fan device 30, for allowing air to be drawn into thechamber 37 of the fan device 30. The lower plate 36 includes a number ofslits 39 or a number pairs of slits 39 formed therein (FIG. 3).

Each of the fan blades 40 includes an upper portion 41 having one ormore ears 42 extended upwardly therefrom and engaged through the slits34 of the upper plate 31, and bent or secured to the upper plate 31, forsecuring the fan blades 40 to the upper plate 31. Each of the fan blades40 includes a lower portion 43 having one or more ears 44 extendeddownwardly therefrom and engaged through the slits 39 of the lower plate36, and bent or secured to the lower plate 36, for securing the fanblades 40 to the lower plate 36. The fan blades 40 may thus be solidlysecured between the outer peripheral portions of the upper plate 31 andthe lower plate 36.

As shown in FIGS. 3-7, each of the fan blades 40 includes a first or aninner segment 45 and a second or an intermediate segment 46 extendedinwardly relative to the bore 38 of the lower plate 36, for scooping theair in the chamber 37 of the fan device 30, and includes a third or anouter segment 47 disposed or secured between the outer peripheralportions of the upper plate 31 and the lower plate 36.

As best shown in FIG. 7, the inner segment 45 of the fan blade 40includes a curvature or a semi-diameter R1 preferably less than thecurvature or the semi-diameter R2 of the intermediate segment 46 of thefan blade 40. The semi-diameter R2 of the intermediate segment 46 of thefan blade 40 is preferably less than the curvature or the semi-diameterR3 of the outer segment 47 of the fan blade 40.

As best shown in FIG. 6, the fan blade 40 includes a cut-off portion 48formed or provided in the inner and lower portion thereof and defined byan inclined or curved and inclined edge 49, such that the inner segment45 of the fan blade 40 includes a height smaller than that of theintermediate segment 46 and the outer segment 47 of the fan blade 40,and such that the outer segment 47 of the fan blade 40 includes a widthsmaller than that of the inner segment 45 and the intermediate segment46 of the fan blade 40. It is preferable that the outer segment 47 ofthe fan blade 40 includes a width equals to or smaller than that of thelower plate 36 of the fan device 30.

In operation, as shown in FIGS. 5 and 8, due to the formation orprovision of the cut-off portions 48 in the fan blades 40, the fandevice 30 thus includes a widely opened lower portion formed and definedby the bore 38 of the lower plate 36 and the chamber 37 of the fandevice 30, for allowing the air to flow through the bore 38 of the lowerplate 36 and deeper into the chamber 37 of the fan device 30, before theair may be contacted and scooped by the fan blades 40.

The smoke exhauster is shown and illustrated in FIGS. 1 and 5 of thedrawing figures to include a single fan device 30 attached to thehousing 10 and driven by one motor 11. However, the smoke exhauster mayalso include two (FIG. 8) or more fan devices 30 attached to the housing10 and each driven by one motor 11.

It is to be noted that the fan blades 40 are shown in the drawingfigures to be secured between and to be perpendicular to the upper plate31 and the lower plate 36. However, the fan blades 40 may also bearranged or disposed to be tilted or inclined relative to the upperplate 31 and the lower plate 36.

Accordingly, the smoke exhauster in accordance with the presentinvention includes an improved fan device for increasing the air drawingeffect to the fan device.

Although this invention has been described with a certain degree ofparticularity, it is to be understood that the present disclosure hasbeen made by way of example only and that numerous changes in thedetailed construction and the combination and arrangement of parts maybe resorted to without departing from the spirit and scope of theinvention as hereinafter claimed.

1. A smoke exhauster comprising: a housing, a motor attached to saidhousing, and a fan device attached to said motor and to be driven bysaid motor, said fan device including: an upper plate, a lower platehaving a bore formed therein, and a plurality of fan blades securedbetween said upper plate and said lower plate, to define a chamberbetween said upper plate and said lower plate of said fan device, saidchamber of said fan device being communicating with said bore of saidlower plate to allow air to flow into said chamber of said fan device,and each of said fan blades including a lower cut-off portion formedtherein to allow the air to flow deeper into said chamber of said fandevice before contacting with said fan blades, and each of said fanblades including an inner segment, an intermediate segment, and an outersegment, said outer segment of said fan blade including a width nogreater than that of said lower plate of said fan device.
 2. The smokeexhauster as claimed in claim 1, wherein said upper plate and said lowerplate each includes a plurality of slits formed therein, each of saidfan blades includes an upper portion and a lower portion each having atleast one ear extended therefrom and engaged through said slits of saidupper and said lower plates, for securing said fan blades between saidupper and said lower plates.
 3. The smoke exhauster as claimed in claim1, wherein each of said fan blades includes an inclined edge defined bysaid lower cut-off portion thereof.
 4. The smoke exhauster as claimed inclaim 1, wherein said inner segment of said fan blade includes a heightsmaller than that of said intermediate segment and said outer segment ofsaid fan blade.
 5. The smoke exhauster as claimed in claim 1, whereinsaid outer segment of said fan blade includes a width smaller than thatof said inner segment and said intermediate segment of said fan blade.6. The smoke exhauster as claimed in claim 1, wherein said intermediatesegment of said fan blade includes a curvature greater than that of saidinner segment of said fan blade.
 7. The smoke exhauster as claimed inclaim 1, wherein said intermediate segment of said fan blade includes acurvature less than that of said outer segment of said fan blade.